The invention relates generally to the detection of objects hidden behind an obscuring surface, and more particularly, to a device and method that use a gas to both detect and display the existence of the hidden objects.
Often in the fields of building construction, renovation, and repair, it would be desirable to generate an “X-Ray” type of view of walls, floors, ceilings, and other obscuring surfaces to find the exact locations of any structural or facilities members hidden behind them. In many cases for safety purposes, it is essential to locate any pipes, wires, or conduits before any penetration of an obscuring wall, floor, or ceiling surface occurs. In other cases, there is a need to find the exact location of a stud or other bracing member behind the obscuring wall surface to use as a strong support for mounting a heavy object to the wall, such as a minor. The mounting screw or screws of the object to be hung must penetrate not only the wallboard, but also the stud since wallboard by itself is typically is not strong enough to hold up heavy objects.
One option to determine what exists behind an obscuring wall is to remove the wall or a part of it. This can be expensive and time consuming. Carpenters for instance, would vastly profit from the ability to plan improvements without the need for opening an existing wall. Such wall openings cause an even greater amount of work due to the required repair, closing, and patching of those walls. Electricians and plumbers would enjoy the ability to determine the exact locations of various obstructions and clear areas behind obscuring wall surfaces so that they could more easily plan their wire or pipe runs. Being able to determine the existence of pipes, wires, conduits, studs, bracing members, and other features would make projects much easier, more efficient, and in many cases, much less expensive.
Home inspectors would like to be able to determine whether various contractors and homeowners have done their work according to applicable construction codes and whether the materials and fabrication techniques are according to applicable requirements. In most cases, construction inspections are required before an obscuring surface is erected. However, cases have arisen, due to timing or other events beyond the control of those involved, where an obscuring surface is put in place before the required inspection could be performed. In such a case, verifying that proper construction techniques were used may require removal of the wall or other obscuring surface, or at least opening access ports through the wall to allow visual inspections. This leads to the additional time and expense to close the (often multiple) access ports of the wall. Because existing devices and methods do not adequately permit an inspector to check construction materials and techniques that are hidden from view behind an obscuring wall, removal of the wall is the only option in some cases. However, if a device and method were provided that would give the inspector a clearer view of the hidden object or construction techniques, such a device and method may enable an inspector to approve the completed construction without requiring that the wall be removed.
Being able to obtain a display of what is located behind a wall, floor, or ceiling surface is desirable for various purposes, such as locating cavities in floor surfaces, joists, and other areas, determining where fasteners should go when assembling any type of non-conductive structures, locating studs behind plastic, or glass walls, and locating live or non-live wires. Other situations would also benefit from a detector or scanner that can provide an image of the structure or features behind an obscuring surface. For example, it is desirable to be able to scan for hidden wall cavities in buildings, scan for hidden compartments in airplane internal cabin structures, analyze non-ferrous boat hulls to determine hidden contraband cavities and/or metal sub-structures, locating hidden items in suitcases, locating contraband at schools and in other places.
Various technologies have been proposed to avoid having to open an obscuring wall to find objects located behind that wall. These range from a simple metal detector comprising a pivoting magnet, to more complex metal detectors (see U.S. Pat. No. 4,853,617), to capacitive sensor systems, to a short-range radar system (see U.S. Pat. No. 5,774,091). A simple “stud finder” has been available for many years that may be used to find the vertical support studs of a wall. In perhaps the simplest case, the stud finder comprises only a magnet mounted so that it may pivot towards ferrous material, such as metal nails, that are used to attach studs to a bottom plate for example. Perhaps the most successful technology used in detecting objects located behind concealing surfaces is the capacitive sensor.
Capacitive detector devices and methods have been provided with many different circuits used to implement them. There are, however, drawbacks to such devices one of which is that they are incremental in nature. They are referred to as being “incremental” because they use discrete capacitive components that are able to provide a detection area that is only as large as the capacitive component itself. Adding additional capacitive components has been attempted but the cost an circuit complexity also undesirably increase. Additionally, a separate display device is needed so that the operator can see what the capacitive detector has detected. Separate displays increase the cost as well as the possibility of failure. In many cases, only one or just a few capacitors are used as detectors. Because of this, and even if they use light emitting diodes (LEDs) or even liquid crystal displays (LCDs), they do not provide a seamless and high resolution picture of the objects behind the obscuring surface. They are limited by the size of the capacitive plate or capacitive sensor device used.
Some effort has been made to provide higher resolution images from capacitive detectors by using more capacitor plates for detection or by providing circuits that control fringe effects in capacitors or provide other such improvements that detract from resolution or accuracy. For example, in one case three capacitive sensors are used, each of which has its own LED display device (see U.S. Pat. No. 6,198,271 to Heger et al.). Regardless of these so-called improvements, such capacitive detector devices provide detection using discrete elements. Providing greater and greater numbers of discrete capacitive detector devices or arrays of detectors in a single housing would cause the need for more wiring, more circuits, and more displays or display elements, all of which can increase the cost and size of a detector significantly. Even then, the detection display will remain incremental in nature and may not provide a seamless picture of the objects behind the obscuring surface. It should also be pointed out that detectors that use discrete devices, such as individual capacitors referred to above, can result in a level of accuracy limited by the size of the discrete device that may still prove to be undesirable.
As used herein, “discrete device” or “discrete component” refers to an electronic component with just one circuit element, either passive (for example, resistor, capacitor, inductor) or active (for example, transistor, diode), as opposed to an integrated circuit that comprises a plurality of miniature components, such as transistors, and other electronic components on a thin rectangle of silicon or other material. An integrated circuit can contain dozens, hundreds, or millions of electronic components.
Such discrete capacitive detection devices and methods only allow the user or operator to determine the presence or absence of structural, wiring, or plumbing members directly under the device. Although the user can physically move the device over the surface of the wall and thereby crudely “map” sub-surface objects, the user is not provided with an integrated, seamless, and contextual “picture” of the undersurface structure.
There has also been identified a need to detect and display the electromagnetic fields of energy sources. Locating the radiating energy source and observing its energy field result in a benefit because, for instance, these fields often interfere with the operation of sensitive electronic equipment in their proximity, and being able to precisely locate and then mitigate against these fields would be efficacious. There has also been speculation in the health community as to whether human exposure to strong electric fields may have detrimental effects on people exposed to them. It would be desirable to provide a detector that can allow detection, localization, and visual mapping of these fields.
Hence, those skilled in the art have recognized a need for a higher resolution device with which hidden objects located behind an obscuring surface may be detected and displayed. A further need has been recognized for a device that uses a display that matches the resolution of the detector of the hidden objects so that a more accurate picture of the objects located behind an obscuring surface may be visualized. It has been further recognized that a detector device that does not need a separate display from the detector component would be desirable. Needs for operation at higher efficiency and a lower cost to manufacture such a device have also been recognized. Furthermore, a device and method for detecting and mapping an electromagnetic radiation source and its electromagnetic fields has also been recognized as desirable. The subject invention satisfies these needs and others.